10.6.5 Using watches with old versions of CVS

If you use the watch features on a repository, it
creates ‘CVS’ directories in the repository and
stores the information about watches in that directory.
If you attempt to use CVS 1.6 or earlier with the
repository, you get an error message such as the
following (all on one line):

cvs update: cannot open CVS/Entries for reading:
No such file or directory

and your operation will likely be aborted. To use the
watch features, you must upgrade all copies of CVS
which use that repository in local or server mode. If
you cannot upgrade, use the watch off and
watch remove commands to remove all watches, and
that will restore the repository to a state which
CVS 1.6 can cope with.